1. Field of the Invention
The present invention relates to a magnetic memory, e.g., a magnetic memory including a magnetoresistive element capable of recording data by supplying a current.
2. Description of the Related Art
Recently, the demands for large-capacity, small-sized information storage devices, represented by a flash memory, are increasing. In the near future, large-volume contents, such as moving images, are likely to be distributed to portable information terminals, so high-speed data transfer is necessary. Accordingly, light-weight, large-capacity information storage devices capable of high-speed transfer are required.
On the other hand, spin-transfer magnetization reversal as a new write principle in a magnetic random access memory (MRAM) as a memory using magnetism is attracting attention as a means for obtaining a capacity at the level of gigabits (see U.S. Pat. No. 5,695,864). The feature of this principle is to supply a current spin-polarized by a fixed layer to a free layer of a magnetoresistive element, and change the direction of magnetization in the free layer in accordance with the direction of the current, thereby writing data. Data is read out by detecting the change in resistance value of the magnetoresistive element by a current, which causes no magnetization reversal. This method is desirable for micropatterning and low power consumption.
As a related technique of this type, a technique which accelerates data read in an MRAM device having an MTJ memory cell is disclosed (see Jpn. Pat. Appln. KOKAI Publication No. 2002-197852).